Method of making laminated tubular section structural members



Apnl 18, 1961 s. MACOMBER 2,979,805

METHOD OF MAKING LAMINATED TUBULAR SECTION STRUCTURAL MEMBERS Original Filed Feb. 7, 1958 3 Sheets-Sheet 1 INVENTOR ATTORNEYS April 18, 1961 s. MACOMBER METHOD OF MAKING LAMINATED TUBULAR SECTION STRUCTURAL MEMBERS Original Filed Feb. 7, 1958 3 SheetSSheet 2 ATTORNEYS Apnl 18, 1961 s. MACOMBER 2,979,805

METHOD OF MAKING LAMINATED TUBULAR SECTION STRUCTURAL MEMBERS Onginal Filed Feb. 7, 1958 3 Sheets-Sheet 3 INVENTOR I/IIIIIIIIIII /IIIIIIIIIIII/ /VV/ 0/4! I? ATTORNEYS United States Patent METHOD OF MAKING LAMINATED TUBULAR SECTION STRUCTURAL MEMBERS Stanley Macomber, Canton, Ohio, assignor to Macomber, Incorporated, Canton, Ohio, a corporation of Ohio Original application Feb. 7, 1958, Ser. No. 713,810. and this application Nov. 25, 1958, Ser. No.

6 Claims. (Cl. 29-155) The invention relates to a method of forming laminated tubular section structural members, and the present application is a division of my copending application, Serial No. 713,810, filed February 7, 1958.

Single ply tubular section structural members of the type referred to have been made for many years in accordance with my Patent No. 2,457,250, issued December 28, 1948. Such a structural member comprises an elongated strip of metal having its longitudinal central portion bent into a substantially triangular tubular bulb, opposite edge portions of the strip being oppositely bent forming substantially flat flanges.

The dimensions of such structural members are limited by the gauge of the steel strips from which they are formed. For instance, permissible flange widths are limited to slightly over twenty times the gauge of the steel strip, and this requires that the terminal edges of the flanges be reinforced with downturned lips.

Originally, such tubular section structural members were made in gauges from 0.060 to a maximum gauge of 0.160", with a bulb of 1% height. Since a deeper bulb permits practical utilization of heavier gauge steel, a 3-inch deep section was later developed using a maximum gauge of 0.230". This is the heaviest gauge in the hot rolled sheet classification, and also, for all practical purposes is the heaviest gauge sheet which may be coiled and uncoiled as is desirable in the manufacture of such structural members.

Thus, in the 3-inch deep V-section as compared with the original 1%," section, applicant gained not only the additional area in the bulb as a result of increased depth and heavier gauge, but also gained a wider flange allowance due to the heavier gauge metal used in the fabrication thereof.

Such tubular, or iv-section, structural members are commonly utilized as chords in fabricated steel joists, beams, girders and other fabricated structural members in which spaced top and bottom chords are connected byan intervening open-web system. It will be evident that the capacity of such fabricated members is limited by the maximum dimensions, strength and capacity of the V-sections utilized as chords therein.

Therefore, these 3-inch deep V-sections are not suitable for use as chords in extremely long trusses, girders, beams, long-span joists and similar large heavy fabricated structural members.

It istherefore an object of the invention to provide a novel and efiicient method of forming tubular of V-section structural members formed of hot rolled sheet strip material. of sufficient capacity for use as. chords in such large heavy fabricated structural members.

Another object of the invention is to provide a method for forming a laminated tubular structural member which will permit doubling in structural effect the maximum gauge of hot-rolled sheet available, by combining two superposed strips of up to 0.230" gauge, giving a combined'o verall gauge of up to 0.460".

Patented Apr. 18, 1961 A further object of the invention is to provide a method for making such a laminated tubular section structural member in which the plural strips of metal are connected together by spot-resistance welding, punching and plugging, or other practical means.

A still further object of the invention is to provide a method for making such laminated tubular section structural members, which includes connecting the laminations together at the longitudinal center line and at lines running longitudinally through the flanges of the section.

Another object of the invention is to provide a method of the character referred to, in which two superposed hot-rolled strips are connected together at their leading ends and then passed longitudinally through suitable forming apparatus.

A further object is to provide such a method in which the two strips are connected together at their longitudinal center line, then formed to desired V-section shape, and then connected together in the flange portions of the finished structural member.

The above objects together with others which will be apparent from the drawings and following description, or which may be later referred to, may be attained by constructing the improved laminated tubular section structural member in the manner hereinafter described in detail and illustrated in the accompanying drawings.

In general terms, the invention may be described as comprising a laminated tubular section structural member comprising two juxtaposed hot rolled steel strips connected together by Welding, or punching and plugging, the longitudinal central portion of the united strips be ing formed into substantially triangular tubular or bulb shape, with oppositely disposed flat flanges at the top of the bulb and terminating in downturned edges.

A longitudinal nailing groove is formed at the top or apex of the triangular bulb and welds are located at spaced points therein to hold the groove to a predetermined definite width.

In forming the laminated V-section structural member, two hot rolled steel strips are superposed and the leading ends thereof are welded together. The laminated strip structure is then moved longitudinally forward through side guides, and the two strips are connected together along their longitudinal center line by welding, punching and plugging, or the like.

The two superposed connected strips are then passed forwardly through forming rolls which form the longitudinal central portion thereof into a substantially triangular tubular bulb with a longitudinal groove at its top or apex, and the edge portions are bent oppositely to form oppositely disposed flat flanges with downturned terminal edges. The flanges are connected together throughout their lengths by welding, punching and plugging, or the like.

Having thus briefiy described the laminated tubular sectional structural member to which the invention pertains, and the method of making the same, reference is now made to the accompanying drawings, in which:

Fig. 1 is a perspective view of a portion of a laminated tubular section structural member embodying the invention;

Fig. 2 is a longitudinal edge elevation of two superposed hot rolled steel strips having their leading ends welded together preparatory to forming a laminated tubular section structural member;

Fig. 3 is a transverse sectional view through two superposed hot rolled steel strips connected at the center line preparatory to being formed into the laminated structural member to which the invention pertains;

Fig. 4 is a transverse sectional view through the super- Fig. 5* is--a--similar--view afterthe triangular-tubulat bulb has been formed;

Fig. 6 is a transverse sectional view through the cpmpleted laminated tubular section structural 5 member; a

Fig. 7iis an enlarged, fragmentary, longitudinal seo 5 tional view through a portion of the completed structural member.showingthemanner in which mill scaleis imbedded between the superposed sheets;

Fig. 8' is an. enlarged, fragmentary, sectional: view showing an alternative method offconnectingthe" two 10 sheets together by punching and pluggingtand, V

Fig. 9 is a diagrammatic view. showingthe method by which the laminated structural member is formed.

The laminated tubular sectionlstructural member, as best shown in Figs. 1' and .6, is formed of 'twohotrolled'i steel strips, the combined thicknesses of which may. be between 0.230 inch and 0.460 inch. Either one, orboth, of the strips forming the laminated structural'member... may be of a maximum gauge of 0.230: inch. 1 The. two strips forming the structuralmember are indicatedzgem. erally at 10 and-10a.

' The longitudinal central portion of the laminated strips; is formed into a substantially triangular tubular portion f or-bulb as indicated at 11. This tubular portion or bulb comprises the fiat bottom wall 12, connected; through the curved bends .13 at each side with the. upwardly converging, substantially 'flat side walls l4'1having1 the spaced, oppositelycur'ved, rounded bends 15,.at-the. apexof the'triangle, forming a longitudinal, slot .16 attheg topof the structuralmember.

The laminated strips are thenbent outwardly,;in ;op-.-. posite directions from theslot 16 forming the oppositely, disposed lateral fiat'fianges '17 located in;a plane parallel; with the fiat bottom wall 12 of the bulb. The terminalj edges .of the flanges-17 are bent downwardly, preferably;

at 90 asin dicated at 18, to stiffen and reinforce ,the; structural member Thetwo; strips; 10 and ;10a-are connected together at the longitudinal center line, as indicated;at-12, and lon-., gitudinally through the flanges, as indicated atZl) and;2l,; as by spot-resistance welding. If desired, the ;strips- 10 and 10a may be connected together by punching as at 22 and plugs shown at 23in Fig. 8, or by any other usual and well known means.

For the purpose of holding the Wldth Of the:Sl Otl0 l'- groove 16 to a definite spacing as wellas toassist'in; stifi'ening and reinforcing the laminated structural memf ber, and holding'it rigidly in theformed condition, welds, as :indicated at 24 may be located at-spacedintervals the entrance to the slot or groove-16.

In such a laminated tubular section-structural member, I owing to the increased thicknessofthe combined strips;v 10 and 10a of which the structural member is..forri1e d, the bulb 11 of the. structural member may .beoflcon siderablygreater depth than impossible under,present..55 practice. I

The flange width may also be considerably increased; over present practice and may .be'slightly over 20 times the combined gauge of-the two strips '10 and 10d. The structural efiectand. capacity ofsuch-a laminated tubular section structural member may thus be greatly increased over present practice, wherein the structural. members are formed of a single hot rolled strip with a maximum gauge of 01230 inch. Y 5 I By using twohot rolled strips 10.and-,10a, each of the 5 maximum gauge of 0.230 inch, an .overall gauge 0f.0.4 60. inch is provided. which would permit doubling .in struc-.. tural effect the maximum gauge ofv hot rolledsheet. avail:

able. 7 a

Thus, large heavy tubular section structural. members, 7 may be produced which will be suitable for useaspchord members in .large heavyfabricated structural. members, fon carrying extremely: heavy. loads, such, sdersba ma ears -i es aadlt ae ik e r a In Fig. 9 is shown diagrammatically e manner in 76 whicharlaminated tubular sectionstruetural-'n'lerriber maybe formed from two hot rolled steel strips, one or both of which may be of a maximum gauge of 0.230 inch, giving an overall maximum gauge of 0.460 inch.

Coils of the hot rolled strip as indicated at 10' and 10a are located in suitable coil boxes at the chargipg end of the apparatus diagrammatically shown ;in Fig. 9i- The strips 10 and 10a are withdrawn from the coils 10' and 10av respectively, and are placed in superposed position and passed through the side guides, indicatedgenerally at 25, to a clamp stand 26 where the leading ends, of 'the two strips are arcewelded together as-indicatedat" 27 in Fig. 2.

It will be understood that each of the strips 10 and 10a may be up to a maximum gauge of;0.23.01inch. The upper strip 10 should be of somewhat greater width than v, the lower strip 10a, as shown in Fig. 3, in order to com:

pensate for the lateral movementof the-stripsrelative to eachother-during the formingoperation, so that the lateral edges of the strips may be flush when thelaminatedi tubular section structural member is-completed.-

The two strips 10 and 10a, with the leading ends thereof welded together as at 27, are then entered intothe power rolls, indicated generally at- 28-which1 advances thesuperpo sed strips through the forming meek amsm.

After passing through power rolls-28,-the superposed-; strips pass through the sliding centerline connector im dicated generally at 29, in which the two strips'are con nected together at the longitudinal center line as by spotresistancewelding, as indicated at 19. Instead of spot-. resistance welding, the two hot rolled strips lo and 10a:- maybe-connected together at this point bypunching-and plugging asshown in Fig. 8, or by other practical method.-'

After being thus connected together at the center line,- the. two superposed, connected strips 10 and 10a 2' then passthrough additional power rolls 30 and side guides 31f and then into the forming mill indicated generally at- -SZ." Thisw forming mill includesaplurality of forming rolls: 33 which form thesuperposedstrips 10'and 10a, progressively as shown in Figs. 4, 5 and 6.

First, the longitudinal central portion of the combined strips is formed into substantially U-shape aseindicateti at.34 in Fig. 4, afterwhich the upper ends of -'the -U aree bent toward each other forming the substantiallytri-r angular bulb 11, as shown in Fig. 5. The terminal edges -of the combined strips are then bent downfoi'ming thea 'terminal flanges 18, as shown in Fig. 6."

The formed laminated tubular section structural. 'me'm-s. berthen passes through .the sliding flangeconnectorin-n. dicated generally at' 35 where the superposed strips-zaree. welded' together longitudinally throughout tire-flange portions 17 and 18, as indicated at 20 and 21'1respectivee.. ly..in-Figs. 1- and 6. The finished structurahmembere thenpasses through the. sliding cut-oflrshearindicatedz. generally at 36,where it may be cut into..any;desireds length.

' As thelaminated tubular section :structural member is": formed of hot rolled strips, mill scale.;will':be loosenedr, upon the strips by the cold roll forming operation. .Such scale will be retained between the opposed. surfaces of the; strips 10 and 10a. within the, struetural'member thusformed.

Since the scale is harder than the steel-strips,; therewill'be'a tendency for the scale to become-slightly bedded in the opposed surfaces of the strips 10pan d ;-10a,-; asindicated at 37; in Fig. 7-. The scale will thus prove; resistant to longitudinal slippage between the *twostrips; in the finished structural members when used -as;chords in fabricated truss members when: they meander-heavy loadings. r r V a It hasbeen found by actual .practice that a laminated structural member of any given total :thiclgnesmmaybg, roll formed with much less -p9w.er thau allfllirpllr m tural member of the same given thickness.

Therefore, while the laminated structural member was developed in order to produce larger and heavier structural members thanthe single-ply structural members of present practice, the invention is not limited to such large, heavy structural members, but includes the laminated structural members formed from a plurality of sheets of gauges in the hot rolled sheet classification, regardless of the combined thickness of the laminations.

Thus, while for the purpose of illustration, the structural member is shown as formed of only two hot-rolled sheets, it should be understood that the lminated structural member may be formed from two or more hotrolled sheets.

From the above it will be seen that the laminated tubular section structural member constructed in the manner herein disclosed may be of greatly increased capacity. Such laminated structural members may be of considerably greater depth than is possible under present practice where such members are formed from a single thickness of hot-rolled strip, and the flange width may greatly exceed the maximum flange width under present practice.

It will also be evident that these laminated structural members are formed of hot-rolled strips which may be coiled and uncoiled as is necessary and desirable in the manufacture of such products.

It will also be seen that the laminated structural member may be formed to desired shape with considerably less power than would be required in the bending and forming a a single-ply steel plate of a gauge equal to the combined thicknesses of the two steel strips from which the laminated structural member is formed.

Laminated structural members made in this manner would be suitable for use as chords in heavy trusses, girders, beams and long-span joists for which purposes the single-ply V-sections of present practice cannot be used. This is possible because the laminated structural member permits doubling in structural effect the maximum gauge of hot rolled steel sheet available.

It will also be evident that this laminated structural member functions without slippage between the two strips of which it is formed when submitted to maximum moment stresses under loading of built-up truss members or the like in which the laminated structural members form the chords.

In the foregoing description, certain terms have been used for brevity, clearness and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated and described herein are by way of example, and the scope of the present invention is not limited to the exact details of construction.

Having now described the'invention or discovery, the construction, the operation, and use of preferred embodiments thereof, and the advantageous new and useful results obtained thereby; the new and useful construction, and reasonable mechanical equivalents thereof ob- 6 vious to those skilled in the art, are set forth in the appended claims.

I claim:

1. The method of making a laminated tubular section structural member which comprises moving two strips of hot-rolled sheet steel longitudinally in superposed relationship with the edges of the lower strip spaced inwardly from the edges of the upper strip, connecting the leading ends of the two strips together, connecting the moving strips together at the longitudinal center line so that they are free to move relatively only from the longitudinal center outward, then roll forming the longitudinal central portion intermediate the longitudinal edges of the moving composite strip downwardly into U-shape, then roll forming the U-shape central portion intermediate the longitudinal edges of the moving composite strip into tubular form with a longitudinal groove in the top side thereof, then bending the moving composite strip oppositely on each side of the groove forming flat flanges with downturned terminal portions with the edges of both strips flush, then connecting the flanges and downturned terminal portions of the two strips together longitudinally throughout the length of said structural member, and deposit welding at spaced points in the entrance to the groove for rigidly holding the walls thereof to a predetermined spacing.

2. The method of making a laminated tubular section structural member as defined in claim 1, in which the two strips are connected together by welding.

3. The method of making a laminated tubular section structural member as defined in claim 2, in which the U-shape central portion of the composite strip is roll formed into triangular tubular form with the longitudinal groove in the apex thereof.

4. The method of making a laminated tubular section structural member as defined in claim 1, in which the two strips are connected together by punching and pluggmg.

5. The method of making a laminated tubular section structural member as defined in claim 4, in which the U-shape central portion of the composite strip is roll formed into triangular tubular form with the longitudinal groove in the apex thereof.

6. The method of making a laminated tubular section structural member as defined in claim 1, in which the U-shape central portion of the composite strip is roll formed into triangular tubular form with the longitudinal groove in the apex thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,840,305 Andrus et al. Jan. 12, 1932 2,086,143 Van Hufiel July 6, 1937 2,326,283 Bonsall Aug. 10, 1943 2,457,250 Macomber Dec. 28, 1948 FOREIGN PATENTS 582,387 Germany Aug. 14, 1933 

